Systems and methods for providing airflow

ABSTRACT

An exemplary embodiment of the present invention provides a silencer. The silencer includes an enclosure with a first airflow path configured to allow air to pass through the enclosure and attenuate noise entering the enclosure. The enclosure also includes an opening configured to provide a second airflow path if the first airflow path is obstructed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.12/489,867, filed Jun. 23, 2009 now U.S. Pat. No. 7,929,295.

BACKGROUND

Modern electronic devices, such as personal computers (“PCs”), servers,and disk arrays, among others, often contain densely packedheat-producing components, such as processors, storage devices, powersupplies, and the like. To prevent overheating, computer systemenclosures often include fans for providing a flow of cooling airthrough the enclosure that draws heat from various electronic componentsand transfers the heat to the outside environment. However, if an airoutlet becomes blocked, the flow of air may be interrupted and heat maybuild up inside the enclosure, which may lead to overheating ofelectronic components. Fans and other electronic components within theenclosure can also be a significant source of environmental noise.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain exemplary embodiments are described in the following detaileddescription and in reference to the drawings, in which:

FIG. 1 is a partial cutaway perspective view of a blade system with asilencer, in accordance with exemplary embodiments of the presentinvention;

FIG. 2 is a partial cutaway side view of the blade system of FIG. 1 withan auxiliary air outlet, in accordance with exemplary embodiments of thepresent invention;

FIG. 3 is a partial cutaway side view of a blade system of FIG. 1wherein the auxiliary air outlet is open, in accordance with exemplaryembodiments of the present invention; and

FIG. 4 is a process flow diagram showing a method of cooling anelectronic device, in accordance with exemplary embodiments of thepresent invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Exemplary embodiments of the present invention relate to systems andmethods for providing airflow in a computer system. An exemplaryembodiment provides a computing system that includes an enclosure withfans that provide airflow through the enclosure to cool the electronicsof the computing system. After the air is drawn through the enclosure,the air exits the enclosure through a silencer that reduces noiseproduced within the enclosure, for example, by the fans. Inside thesilencer, the air flows through a first airflow path surrounded by soundabsorption material and includes a first air outlet disposed at arearward facing surface of the silencer.

If the first airflow path becomes obstructed, a second airflow path maybe opened to enable the enclosure to continue receiving cool air. In anexemplary embodiment of the present invention, the second airflow pathmay include an auxiliary air outlet disposed on another surface of theenclosure. The second airflow path may be activated by opening a paneldisposed over the auxiliary air outlet. For example, the increased airpressure inside the silencer due to the blockage of the first exhaustmay force the panel to open. Exemplary embodiments of the presentinvention may be used in any suitable electronic device, for example, adisk array, a personal computer, a blade server or the like.

FIG. 1 is a partial cutaway perspective view of a blade system 100 witha silencer, in accordance with exemplary embodiments of the presentinvention. The blade system 100 may include one or more computing blades102 mounted inside a blade enclosure 104. The blades 102 may include anykind of blade, for example, server blades, switching blades, routingblades, storage blades, and the like. The blade enclosure 104 houses theblades 102 and may provide various functions of the blade system 100,for example, providing power to the blades 102, networking the blades102 to one another and to external devices, and cooling.

The blade enclosure 104 may include power receptacles 106 for couplingthe blade system 100 to a power source such as an alternating-current(AC) power source. The blade system 100 may further include one or morepower supply units (PSUs) that receive AC power through the powerreceptacle 106 and convert the AC power to direct-current (DC) power.The blade system 100 may also include circuitry for distributing the DCpower from the PSUs to the one or more blades 102. Moreover, the bladeenclosure 104 may include one or more fans 108 that draw cooling airinto the blade enclosure 104 to cool the blade 102 electronics.

The enclosure 104 may be open at the front 110 to enable the blades 102to be easily inserted and removed and to provide user access to theblade's 102 controls, communications ports, status indicators, and thelike. The fans 108 may be mounted at the rear 112 of the blade enclosure104. Further, the blade enclosure may include supports 114 mounted tothe bottom of the enclosure. The supports 114 may be wheels configuredto increase the portability of the blade enclosure 104. Although, theblade enclosure 104 shown in FIG. 1 is a tower-style enclosure, it willbe appreciated that the blade enclosure 104 may also be configured as arack-mount enclosure.

In an exemplary embodiment of the present invention, the blade system100 may include a silencer 116 that enables exhaust air to exit theblade system 100 while also reducing the amount of noise produced byblade system 100. The silencer 116 may include an enclosure 118 withreceptacle openings 120 and fan openings 122. The silencer mounts to therear 112 of the blade enclosure 104 such that the receptacle openings120 align with the power receptacles 106 and the fan openings 122 alignwith the fans 108. The receptacle openings 120 provide access to thepower receptacles 106 through the silencer 116. The fan openings 122provide an air-path through the silencer 116 that enables exhaust air toexit the blade enclosure 104.

The silencer 116 also includes sound absorbing material 124 disposed onan inside wall of the fan openings 122 and configured to attenuate noisegenerated in the blade enclosure 104. The sound absorbing material mayinclude, for example, foam, a mesh of fibrous material, a metal mesh, aplastic mesh, or a combination thereof. In some exemplary embodiments ofthe present invention, the silencer 116 may be included in the bladeenclosure 104 rather than mounted to the blade enclosure 104 as aseparated piece.

It will be appreciated that, if the fan openings 122 become obstructed,the amount of air flowing through the blade enclosure 104 may bereduced. Therefore, to prevent overheating of the blades 102 that mayotherwise result from a blockage of the fan openings 122, the silencer116 may include an auxiliary air outlet that enables air to pass throughthe silencer 116 if the fan openings 122 become obstructed, as will bediscussed further in reference to FIGS. 2 and 3. This auxiliary airoutlet provides an alternate airflow path that may be activated by anincreased air pressure within the silencer 116. In this way, cooling airmay continue to flow through the blade enclosure 102, and theprobability of overheating may be reduced.

FIG. 2 is a partial cutaway side view of the blade system of FIG. 1 withan auxiliary outlet, in accordance with exemplary embodiments of thepresent invention. As discussed in reference to FIG. 1, the blade system100 includes a blade enclosure 104 with fans 108 for circulating airthrough the blade enclosure 104 and a silencer 116 with fan openings 122aligned with fans the 108 and configured to attenuate noise. Inexemplary embodiments of the present invention, the silencer 118includes an auxiliary air outlet 200 configured to provide an alternateairflow path if the fan openings 122 become obstructed. The auxiliaryair outlet 200 may be disposed on any side of the silencer enclosure118. In some exemplary embodiments, the auxiliary air outlet 200 may bedisposed on a side of the silencer enclosure 118 that is perpendicularto the side of the silencer enclosure 118 that has the fan openings 122.In this way, the probability of blocking both the fan openings 122 andthe auxiliary air outlet 200 may be reduced. Additionally, multipleauxiliary air outlets 200 may be disposed on opposing sides of thesilencer 116.

Furthermore, the auxiliary air outlet 200 may include a panel 202 thatcovers the auxiliary air outlet 200 and enables the outlet 200 to beopened or closed. In exemplary embodiments, the panel 202 may be coupledto the silencer enclosure 118 via a hinge 204. The auxiliary air outlet200 may be closed if the fan openings 122 are unobstructed and opened ifthe fan openings 122 are partially or completely obstructed or airflowthrough the silencer 116 is otherwise restricted. The opening of theauxiliary air outlet 200 activates the alternate airflow path of thesilencer 116.

The alternate airflow path bypasses the fan openings 122 and couples thefans 108 to the auxiliary air outlet 200. The alternate airflow path maybe provided, in part, by a vertical channel disposed between thesilencer 116 and the rear 112 of the blade enclosure 104. In exemplaryembodiments, the vertical channel may be formed by air gaps 206 betweenthe sound absorbing material 124 and the rear 112 of the blade enclosure104. The gaps 206 may be sized to provide suitable airflow from the fan108 to the auxiliary air outlet 200. Accordingly, it will be appreciatedthat the width of the gaps 206 may increase according to the number offans upstream from the gap 206.

In exemplary embodiments of the present invention, the auxiliary airoutlet 200 may be coupled to an alarm 210, which may be triggered by theopening of the auxiliary air outlet 200. For example, the movement ofthe panel 202 away from the silencer enclosure 118 may cause aninterruption of an electrical connection disposed between the panel 202and the enclosure 118. In other embodiments, the movement of the panel202 may cause a switch to be depressed.

Triggering the alarm 210 may cause the alarm 210 to generate a warningsignal. In some exemplary embodiments, the warning signal may include anaudible tone generated by the alarm. In other exemplary embodiments, thewarning signal may include illuminating a light, for example, a lightemitting diode (LED) disposed at the front 110 of the blade enclosure104. Generating a warning signal may also include generating anelectronic warning message that may be sent to a user through a network.Accordingly, the alarm 210 may send an electrical signal to the bladesystem 100 that causes the blade system 100 to generate a warningmessage, such as a text message. The warning message may be sent to aspecified device via the network to which the blade system 100 iscoupled. For example, the warning message may be sent to a user's emailaccount, instant messaging service, cell phone, pager, and the like.

In exemplary embodiments of the present invention, opening the outlet200 may be triggered by the air pressure inside the silencer 116. FIG. 2depicts the silencer with the auxiliary outlet 200 closed and the fanopenings 122 unobstructed. Under this condition, the fans 108 draw air208 into the blade enclosure 104 from the front 110 of the bladeenclosure 104. The cooling air 208 flows over the electronics disposedon the blades 102 and exits the blade enclosure 104 through the fans108. The air 208 then flows through the fan openings 122 of the silencer116. Accordingly, the air pressure inside the silencer 116 will be closeor equal to the air pressure outside the silencer 116, and the auxiliaryoutlet 200 will remain closed. However, if the fan openings 122 becomepartially or completely blocked, the air pressure inside the silencer116 may increase, causing the auxiliary air outlet 200 to open, asdescribed in reference to FIG. 3.

FIG. 3 is a partial cutaway side view of the blade system of FIG. 1wherein the auxiliary air outlet 200 is open, in accordance withexemplary embodiments of the present invention. As shown in FIG. 3, theblade system 100 has been positioned against a wall or some otherobstruction, so that the fan openings 122 are substantially blocked. Theair blown by the fans 108 cannot exit through the fan openings 122 andtherefore circulates within the silencer 116, as indicated by the arrows300. Thus, the backpressure on the fans 108 increases, which reduces theairflow 208 through the blade enclosure 104. Additionally, the airpressure inside the silencer 116 may also increase substantially. If theair pressure inside the silencer 116 exceeds a certain threshold, theauxiliary air outlet 200 opens, enabling the air to exit the silencer116 through the alternate airflow path, as indicated by the arrows 302.In this way, the flow of cooling air 208 through the blade enclosure 104is maintained even if the fan openings 122 are obstructed. In exemplaryembodiments of the present invention, the air pressure inside thesilencer 116 triggers the auxiliary air outlet 200 to open.

In some exemplary embodiments, the panel 202 may be spring loaded. Forexample, the hinge 204 may include a spring that biases the panel 202open or closed. If the spring biases the panel 202 closed, the auxiliaryair outlet 200 may open if the air pressure inside the silencer 116 ishigh enough to overcome the bias of the spring. Furthermore, the degreeto which the auxiliary air outlet 200 opens may be proportional to thedegree of blockage of the fan openings 122. As the fan openings 122become increasingly blocked, the air pressure inside the silencer 116will increase and the auxiliary air outlet 200 will open wider.Conversely, if the fan openings 122 become unblocked, the air pressureinside the silencer 116 will decrease and the auxiliary air outlet 200may shut again. Accordingly, the auxiliary air outlet 200 may shutautomatically in response to the unblocking of the fan openings 108.

In other exemplary embodiments, the auxiliary air outlet 200 may includea detent mechanism that keeps the auxiliary air outlet 200 closed untila certain level of internal air pressure is reached inside the silencer116. Further, the auxiliary air outlet 200 may also include a springthat biases the panel 202 open. Therefore, the auxiliary air outlet 200may open when the air pressure inside the silencer 116 plus the bias ofthe spring is greater than the force used to overcome the detentmechanism. Once triggered, the auxiliary air outlet 200 may stay openuntil a user remedies the obstruction of the fan openings 122 and closesthe auxiliary air outlet 200 manually.

FIG. 4 is a process flow diagram showing a method of cooling anelectronic device, in accordance with exemplary embodiments of thepresent invention. The method is generally referred to by the referencenumber 400. At block 402, the method begins.

At block 404, a flow of air through a first airflow path is provided.Noise is attenuated in the first airflow path, as shown at block 406. Atblock 408, a second airflow path is opened if the first airflow pathbecomes obstructed. The method ends at block 410.

1. A silencer, comprising: an enclosure comprising a first airflow pathconfigured to allow air to pass through the enclosure and attenuatenoise entering the enclosure; and the enclosure further comprising anopening configured to provide a second airflow path if the first airflowpath is obstructed.
 2. The silencer of claim 1, wherein the secondairflow path comprises a channel that couples the first airflow path andthe second airflow path.
 3. The silencer of claim 1, comprising a paneldisposed over the opening and biased toward a closed position.
 4. Thesilencer of claim 3, wherein the panel is configured to open in responseto air pressure inside the silencer.
 5. The silencer of claim 3, whereinthe panel is configured to close automatically if the first airflow pathbecomes unobstructed.
 6. The silencer of claim 1, wherein the silenceris configured to provide an electrical signal to an alarm to indicatewhether the panel is open.
 7. The silencer of claim 1, wherein theenclosure is configured to mount to a blade enclosure.
 8. A bladeenclosure comprising: a silencer comprising: an enclosure mounted to theblade enclosure and comprising a first airflow path configured to allowair to pass through the enclosure and attenuate noise entering theenclosure; and the enclosure further comprising an opening configured toprovide a second airflow path if the first airflow path is obstructed.9. The blade enclosure of claim 8, wherein the second airflow pathcomprises a channel that couples the first airflow path and the secondairflow path.
 10. The blade enclosure of claim 8, comprising a paneldisposed over the opening and biased toward a closed position.
 11. Theblade enclosure of claim 10, wherein the panel is configured to open inresponse to air pressure inside the silencer.
 12. The blade enclosure ofclaim 10, wherein the panel is configured to close automatically if thefirst airflow path becomes unobstructed.
 13. The blade enclosure ofclaim 8, wherein the silencer is configured to provide an electricalsignal to an alarm disposed on the blade enclosure to indicate whetherthe panel is open.
 14. A method of attenuating noise in an electronicdevice, comprising: providing a first airflow path configured to allowair to pass through an enclosure and attenuate noise entering theenclosure from the electronic device; and providing an opening in theenclosure, the opening configured to provide a second airflow path ifthe first airflow path is obstructed.
 15. The method claim 14, whereinthe second airflow path comprises a channel that couples the firstairflow path and the second airflow path.
 16. The method claim 14,comprising disposing a panel over the opening and biasing the paneltoward a closed position.
 17. The method claim 16, wherein the panel isconfigured to open in response to air pressure inside the silencer. 18.The method claim 16, wherein the panel is configured to closeautomatically if the first airflow path becomes unobstructed.
 19. Themethod claim 14, comprising disposing an alarm on the blade enclosure,the alarm configured to receive an electrical signal that indicateswhether the panel is open.
 20. The method claim 14, wherein theenclosure is configured to mount to a blade enclosure.